U.S. patent application number 10/501452 was filed with the patent office on 2005-12-08 for solvent-soluble block copolymide composition and process for producing the same.
Invention is credited to Hori, Shinichiro, Ishii, Hiroyuki, Itatani, HIroshi, Jin, Xingzhou, Miyamura, Masataka, Taniguchi, Akihito.
Application Number | 20050272907 10/501452 |
Document ID | / |
Family ID | 26625510 |
Filed Date | 2005-12-08 |
United States Patent
Application |
20050272907 |
Kind Code |
A1 |
Jin, Xingzhou ; et
al. |
December 8, 2005 |
Solvent-soluble block copolymide composition and process for
producing the same
Abstract
The invention provides a block copolymerization polyimide
composition comprising a block copolymerization polyimide obtained
by heating a tetracarboxylic dianhydride and a diamine in at least
one solvent selected from a ketone, an ether and an ester and in
the presence of a catalyst generated from a lactone and a base, a
positive type block copolymerization polyimide composition or ink
containing a photooxygenation agent, and processes of producing
them. The block copolymerization polyimide composition of the
invention is never whitened even in the air.
Inventors: |
Jin, Xingzhou;
(Yokohama-Shi, Kanagawa, JP) ; Ishii, Hiroyuki;
(Yokohama-Shi, Kanagawa, JP) ; Miyamura, Masataka;
(Kamakura-Shi, Kanagawa, JP) ; Itatani, HIroshi;
(Yokohama-Shi, Kanagawa, JP) ; Hori, Shinichiro;
(Yokohama-Shi, Kanagawa, JP) ; Taniguchi, Akihito;
(Kanagawa, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Family ID: |
26625510 |
Appl. No.: |
10/501452 |
Filed: |
November 4, 2004 |
PCT Filed: |
January 15, 2003 |
PCT NO: |
PCT/JP03/00252 |
Current U.S.
Class: |
528/310 |
Current CPC
Class: |
C08G 73/1032 20130101;
G03F 7/0392 20130101; C08G 73/1021 20130101; G03F 7/0233 20130101;
C08G 73/10 20130101 |
Class at
Publication: |
528/310 |
International
Class: |
C08G 069/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2002 |
JP |
2002-5413 |
Jan 15, 2002 |
JP |
2002-5414 |
Claims
What we claim is:
1. A block copolymerization polyimide composition, wherein a block
copolymerization type polyimide obtained from a tetracarboxylic
dianhydride and a diamine is dissolved in at least one solvent
selected from a ketone, an ether and an ester.
2. The block copolymerization polyimide composition according to
claim 1, wherein the block copolymerization polyimide is obtained
by heating a tetracarboxylic dianhydride and a diamine in at least
one solvent selected from a ketone, an ether and an ester and in
the presence of a catalyst resulting from a lactone and a base.
3. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the tetracarboxylic dianhydride is at least
one selected from the group consisting of
3,3',4,4'-biphenyltetracarboxylic dianhydride,
3,3',4,4'-benzophenonetetracarboxylic dianhydride,
3,3',4,4'-biphenyl ether tetracarboxylic dianhydride),
3,3',4,4'-diphenylsulfonetetracarboxylic dianhydirde (DSDA),
bicyclo(2,2,2)-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride,
1,2,4,5-cyclohexanetetracarboxylic dianhydride,
2,2-bis(3,4-dicarboxyphen- yl)hexafluoropropane dianhydride,
pyromellitic dianhydride, and
5-(2,5-dioxotetra-hydrofuryl)-3-methyl-3-cyclohexne-1,2-dicarboxylic
anhydride.
4. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the diamine is at least one selected from the
group consisting of siliconediamine, bis(3-aminopropyl)ether
ethane, 3,3'-diamino-4,4'-dihydroxydiphenylsulfone,
4,4'-diamino-3,3'-dihydroxybi- phenyl,
2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane,
siloxanediamine, bis(3-aminopropyl) ether ethane,
N,N-bis(3-aminopropyl)e- ther, 1,4-bis(3-aminopropyl)piperazine,
isophoronediamine, 1,3'-bis(aminomethyl)cyclohexane,
3,3'-dimethyl-4,4'-diamino-dicylohexylm- ethane, 4,4'-methylenebis
(cyclohexylamine), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl
ether, 3,3-diaminodiphenyl ether, 4,4'-diamino-diphenylsulfone,
3,4'-diamino-diphenylsulfone, 3,3'-diamino-diphenylsulfone,
2,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)benzene (m-TPE),
1,3-bis(3-aminophenoxy)benzene,
2,2-bis[4-(4-aminophenoxy)phenyl]propane,
2,2-bis[4-(4-aminophenoxy) phenyl]hexafluoropropane,
bis[4-(4-aminophenoxy)phenyl] sulfone,
bis[4-(3-aminophenoxy)phenyl]sulfone,
4,4'-bis(4-aminophenoxy)biphenyl, 1,4-bis(4-aminophenoxy) benzene,
4,4'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide,
3,3'-diaminodiphenylsulfide,
3,3'-diamino-4,4'-dihydorxydipheylsulfone, 2,4-diaminotoluene,
2,5-diaminotoluene, 3,5-diaminobenzoic acid, 2,6-diaminopyridine,
4,4'-diamino-3,3'-dimethoxy-biphenyl,
4,4'-diamino-3,3'-dimethylbiphenyl, and
9,9'-bis(4-aminophenyl)fluorene.
5. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the ketone is at least one selected from the
group consisting of methyl ethyl ketone, methyl propyl ketone,
methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl
ketone, methyl n-hexyl ketone, diethyl ketone, diisopropyl ketone,
diisobutyl ketone, cyclopentanone, cylcohexanone,
methylcyclohexanone, acetylacetone, diacetone alcohol, and
cyclohexen-1-one.
6. The block copolymerization polyimide composition according to
claim 1, wherein the ether is at least one selected from the group
consisting of dipropyl ether, diisopropyl ether, dibutyl ether,
tetrahydrofuran, tetrahydropyran, ethyl isoamyl ether,
ethyl-t-butyl ether, ethyl benzyl ether, cresyl methyl ether,
anisole, and phenetole.
7. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the ester is at least one selected from the
group consisting of methyl acetate, ethyl acetate, propyl acetate,
isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate,
isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate,
methylcyclohexyl acetate, benzyl acetate, methyl acetoacetate,
ethyl acetoacetate, methyl propionate, ethyl propionate, butyl
propionate, benzyl propionate, methyl butyrate, ethyl butyrate,
isopropyl butyrate, butyl butyrate, isoamyl butyrate, methyl
lactate, ethyl lactate, butyl lactate, ethyl isovalerate, isoamyl
isovalerate, diethyl oxalate, dibutyl oxalate, methyl benzoate,
ethyl benzoate, propyl benzoate, and methyl salicylate.
8. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the solvent containing a ketone, an ether or
an ester contains at least one selected from the group consisting
of N-methylpyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, and dimethylsulfoxide.
9. The block copolymerization polyimide composition according to
claim 2, wherein the lactone is .gamma.-valerolactone, and the base
is at least one of pyridine and N-methylmorpholine.
10. The block copolymerization polyimide composition according to
claim 1 or 2, wherein the block copolymerization polyimide has a
weight-average average molecular weight of 10,000 to 200,000 as
calculated on a polystyrene basis.
11. A positive type photosensitive polyimide composition, which
comprises a block copolymerization polyimide comprising a
tetracarboxylic dianhydride and a diamine and soluble in at least
one solvent of an ether, a ketone and an ester, and a
photooxygenation compound.
12. A positive type photosensitive block copolymerization polyimide
ink composition, which comprises a filler that is insoluble in a
solvent.
13. A process of producing a block copolymerization polyimide
composition, comprising steps of heating a tetracarboxylic
dianhydride and a diamine in a solvent that contains at least one
of a ketone, an ether or an ester and in the presence of an acid
catalyst generated from a lactone and a base to form a polyimide
oligomer, and adding either one of a tetracarboxylic dianhydride or
a diamine to said polyimide oligomer for reaction therewith.
14. A process of producing a block copolymerization polyimide
composition, comprising steps of heating a tetracarboxylic
dianhydride and a diamine in a solvent selected from the group
consisting of N-methylpyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide and N,N-dimethylsulfoxide and in the presence
of an acid catalyst generated from a lactone and a base to form a
polyimide oligomer, then adding either one of a tetracarboxylic
dianhydride or a diamine to said polyimide oligomer for reaction
therewith, then subjecting a reaction product to precipitation
using a poor solvent, filtration and drying, and finally dissolving
a resulting product in a solvent comprising at least one of a
ketone, an ether and an ester.
15. The process of producing a block copolymerization polyimide
composition according to claim 14, wherein the lactone is
.gamma.-valerolactone, and the base is at least one of pyridine and
N-methylmorpholine.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a solvent-soluble polyimide
composition. Having superior heat resistance, electrical
insulation, mechanical properties and chemical resistance,
polyimides now find wide applications in the form of electrical
parts, electronic parts, semiconductor parts, communications
equipments and their circuit parts, and peripheral equipments.
[0002] Polyimide resins, because of being less soluble in organic
solvents, must be converted in polar solvents to polyamide acids,
and then heated and dehydrated into films.
[0003] Recently discovered solvent-soluble polyimides have been
used in coating applications and in the form of liquid crystal
orientation films and insulating films for flexible substrates.
[0004] As solvents for dissolving polyimides therein, polar
solvents such as N-methylpyrrolidone, N,N-dimethyl-formamide,
N,N-dimethylacetylamide and dimethylsulfoxide are used.
[0005] Problems with polyimide varnishes and polyimide inks with
which non-aqueous solvents are used are that when used in an
environment having a relative humidity of 50% or higher, the
surfaces of the resulting films or moldings become white.
[0006] Polyimide films, moldings, etc., once whitened, offer
problems that even upon heated or dried, not only are films having
toughness inherent in polyimides obtained, but also their own
electrical or other properties are never obtained.
[0007] This whitening phenomenon, for the most part, would be due
to the fact that polar solvents used for dissolution of polyimides,
for instance, N-methylpyrrolidone, N,N-dimethylformamide and
dimethylsulfoxide, absorb atmospheric moisture due to their high
moisture absorption properties.
[0008] When polyimide resins dissolved in such solvents are used at
coating or other steps, it is required to blow dry air or nitrogen
gas into a coating system or provide it with a cover for preventing
entrance of moisture from outside.
[0009] When polyimides are used with precision equipments such as
those made of electronic materials, it is necessary to remove
foreign or impure matters derived from them by means of precision
filtration systems. In this case, too, it is required to replace
atmospheres in the filtration systems or receivers such as bins by
dried air or nitrogen gas or provide them with coverings for
preventing entrance of moisture from outside.
[0010] When it comes to a process of making ink using polyimide
resins, it is likewise necessary to blow dried air or nitrogen gas
in a step of mixing it with fillers by roll or mill means, or
provide the whole of an associated system with a cover for
preventing entrance of moisture from outside.
[0011] To meet demands for electronic equipments having higher
densities and higher degrees of integration, photo-sensitive
polyimides that enable precise patterns to be formed by exposure
are now used.
[0012] So far, a negative type of photosensitive polyimide has been
used. In this case, development of an exposed portion is carried
out using an organic solvent after that portion is converted by a
crosslinking reaction to a three-dimensional, insoluble gel.
However, a crosslinking type of photosensitive material is
unfavorable for high-precision micro-processing because an exposed
portion swells upon development by an organic solvent.
[0013] In some cases, a film whitened under the influence of
moisture at a coating step may become transparent after prebaking.
However, even such a transparent film becomes difficult to handle
because of denaturing of the photooxygenation agent such as
naphthoquinonediazides by moisture absorption. Problems with
whitened polyimide films are that riot only are any films having
toughness inherent in polyimides obtainable, but also their own
electrical properties, etc. are not obtainable.
[0014] A primary object of the present invention is, therefore, to
provide a solvent-soluble block copolymerization polyimide
composition that is substantially free from whitening phenomena
ascribable to atmospheric air or the like. Another object of the
invention is to provide a positive type photosensitive polyimide
that has high resolution and reliability without being swollen by
an aqueous alkali solution used as a developing solution.
SUMMARY OF THE INVENTION
[0015] The present invention provides a block copolymerization
polyimide composition, wherein a block copolymerization type
polyimide obtained from a tetracarboxylic dianhydride and a diamine
is dissolved in at least one solvent selected from a ketone, an
ether and an ester.
[0016] In the block copolymerization polyimide composition of the
invention, the block copolymerization polyimide has been obtained
by heating the tetracarboxylic dianhydride and diamine in at least
one solvent selected from a ketone, an ether and an ester and in
the presence of a catalyst resulting from a lactone and a base.
[0017] In the block copolymerization polyimide composition of the
invention, the tetracarboxylic dianhydride is at least one selected
from the group consisting of 3,3',4,4'-biphenyltetracarboxylic
dianhydride (BPDA), 3,3',4,4'-benzophenonetetracarboxylic
dianhydride (BTDA), 3,3',4,4'-biphenyl ether tetracarboxylic
dianhydride (OPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic
dianhydride (DSDA),
bicyclo(2,2,2)-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD),
1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA),
pyromellitic dianhydride (PMDA),
2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA),
and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexn-
e-1,2-dicarboxylic anhydride (CP).
[0018] In the block copolymerization polyimide composition of the
invention, the diamine is at least one selected from the group
consisting of siliconediamine, bis(3-aminopropyl)ether ethane,
3,3'-diamino-4,4'-dihydroxydiphenylsulfone (SO2-HOAB),
4,4'-diamino-3,3'-dihydroxybiphenyl (HOAB),
2,2-bis[4-(4-aminophenoxy)phe- nyl]hexafluoropropane (HOCF3AB),
siloxanediamine, bis(3-aminopropyl)ether ethane,
N,N-bis(3-aminopropyl)ether, 1,4-bis(3-aminopropyl)piperazine,
isophoronediamine, 1,3'-bis(aminomethyl)cyclohexane,
3,3'-dimethyl-4,4'-diaminodicylohexylmethane, 4,4'-methylenebis
(cyclohexylamine), 4,4'-diaminodiphenyl ether (p-DADE),
3,4'-diaminodiphenyl ether (m-DADE), 3,3-diaminodiphenyl ether,
4,4'-diamino-diphenylsulfone (p-DDS), 3,4'-diamino-diphenylsulfone,
3,3'-diamino-diphenylsulfone, 2,4'-diaminodiphenyl ether,
1,3-bis(4-aminophenoxy)benzene (m-TPE),
1,3-bis(3-aminophenoxy)benzene (APB),
2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP),
2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HF-BAPP),
bis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS),
bis[4-(3-aminophenoxy)phen- yl]sulfone (m-BAPS),
4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 1,4-bis(4-aminophenoxy)
benzene (p-TPE), 4,4'-diaminodiphenylsulfide (ASD),
3,4'-diaminodiphenylsulfide, 3, 3'-diaminodiphenylsulfide,
3,3'-diamino-4,4'-dihydorxydipheylsulfone, 2,4-diaminotoluene
(DAT), 2,5-diaminotoluene, 3,5-diaminobenzoic acid (DABz),
2,6-diaminopyridine (DAPy), 4,4'-diamino-3,3'-dimethoxy-biphenyl
(CH3OAB), 4,4'-diamino-3,3'-dimethylbiphenyl (CH3AB), and
9,9'-bis(4-aminophenyl)fl- uorene (FDA).
[0019] In the block copolymerization polyimide composition of the
invention, the ketone is at least one selected from the group
consisting of methyl ethyl ketone, methyl propyl ketone, methyl
isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone,
methyl n-hexyl ketone, diethyl ketone, diisopropyl ketone,
diisobutyl ketone, cyclopentanone, cylcohexanone,
methylcyclohexanone, acetylacetone, diacetone alcohol, and
cyclohexen-1-one.
[0020] In the block copolymerization polyimide composition of the
invention, the ether is at least one selected from the group
consisting of dipropyl ether, diisopropyl ether, dibutyl ether,
tetrahydrofuran, tetrahydropyran, ethyl isoamyl ether,
ethyl-t-butyl ether, ethyl benzyl ether, cresyl methyl ether,
anisole and phenetole.
[0021] In the block copolymerization polyimide composition of the
invention, the ester is at least one selected from the group
consisting of methyl acetate, ethyl acetate, propyl acetate,
isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate,
isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate,
methylcyclohexyl acetate, benzyl acetate, methyl acetoacetate,
ethyl acetoacetate, methyl propionate, ethyl propionate, butyl
propionate, benzyl propionate, methyl butyrate, ethyl butyrate,
isopropyl butyrate, butyl butyrate, isoamyl butyrate, methyl
lactate, ethyl lactate, butyl lactate, ethyl isovalerate, isoamyl
isovalerate, diethyl oxalate, dibutyl oxalate, methyl benzoate,
ethyl benzoate, propyl benzoate and methyl salicylate.
[0022] In the block copolymerization polyimide composition of the
invention, the solvent containing a ketone, an ether or an ester
contains at least one selected from the group consisting of
N-methylpyrrolidone, N,N-dimethyl-formamide, N,N-dimethylacetamide
and dimethylsulfoxide.
[0023] In the block copolymerization polyimide composition of the
invention, the lactone is .gamma.-valerolactone, and the base is at
least one of pyridine and N-methylmorpholine.
[0024] In the block copolymerization polyimide composition of the
invention, the block copolymerization polyimide has a
weight-average average molecular weight of 10,000 to 200,000 as
calculated on a polystyrene basis.
[0025] The present invention also provides a positive type
photosensitive polyimide composition that comprises a block
copolymerization polyimide comprising a tetracarboxylic dianhydride
and a diamine and soluble in at least one solvent of an ether, a
ketone and an ester and a photooxygenation compound.
[0026] The positive type photosensitive block copolymerization
polyimide ink composition further comprises a filler that is
insoluble in a solvent.
[0027] Further, the present invention provides a process of
producing a block copolymerization polyimide composition,
comprising steps of heating a tetracarboxylic dianhydride and a
diamine in a solvent that contains at least one of a ketone, an
ether or an ester and in the presence of an acid catalyst generated
from a lactone and a base to form a polyimide oligomer, and adding
either one of a tetracarboxylic dianhydride or a diamine to said
polyimide oligomer for reaction therewith.
[0028] Furthermore, the present invention provides a process of
producing a block copolymerization polyimide composition comprising
steps of heating a tetracarboxylic dianhydride and a diamine in a
solvent selected from the group consisting of N-methylpyrrolidone,
N,N-dimethylformamide, N,N-dimethylacetamide and
N,N-dimethylsulfoxide and in the presence of an acid catalyst
generated from a lactone and a base to form a polyimide oligomer,
then adding either one of a tetracarboxylic dianhydride or a
diamine to said polyimide oligomer for reaction therewith, then
subjecting the reaction product to precipitation using a poor
solvent, filtration and drying, and finally dissolving the
resulting product in a solvent comprising at least one of a ketone,
an ether and an ester.
BEST MODE OF CARRYING OUT THE INVENTION
[0029] According to the invention, it has now been found that with
a polyimide composition comprising a specific polyimide and a
solvent comprising at least one of a ketone, an ether and an ester,
it is possible to form an easy-to-handle polyimide film or other
like products that are less affected by ambient moisture and more
resistant to whitening or other defects and so have improved
properties.
[0030] It has also been found that if the starting materials are
dissolved in a solvent comprising at least one of a ketone, an
ether and an ester or they are allowed to react with each other in
other solvent to form a polyimide that is dissolved in a poor
solvent upon precipitation, it is then again possible to obtain a
solvent-soluble polyimide composition that has improved
properties.
[0031] Further, it has been found that by making use of an acid
catalyst generated from at least either one of
.gamma.-valerolactone and a weak base such as pyridine and
N-methylmorpholine and consecutive reactions for synthesis, it is
possible to gain molecular-level controls of the bonding between
the tetracarboxylic dianhydride and the diamine, the degree of
polymerization of polyimide, and the physical properties and
photosensitization properties of polyimide.
[0032] Still further, it has been found that by introducing
phenolic hydroxyl groups in the main chain of polyimide in
combination with a naphthoquinonediazide that is photooxygenation
agent, it is possible to provide a positive type polyimide that is
soluble in an alkaline aqueous solution and has high
resolution.
[0033] Furthermore, it has been found that it is possible to
provide a photosensitive polyimide ink and its production process,
wherein phenolic hydroxyl groups are introduced in the main chain
of polyimide and a photooxygenation agent plus a filler, whereby
the polyimide ink is made soluble in an alkaline aqueous solution
and a sufficient solubility difference is so created between an
exposed portion and an unexposed portion that the polyimide ink is
less affected by ambient moisture.
[0034] Preferably but no exclusively, the tetracarboxylic
dianhydride used for the synthesis of the inventive polyimide
includes at least one selected from the group consisting of
3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA),
3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA),
3,3',4,4'-biphenyl ether tetracarboxylic dianhydride (OPDA),
3,3',4,4'-diphenylsulfonetetracarboxylic dianhydirde (DSDA),
bicyclo(2,2,2)-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCD),
1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA),
pyromellitic dianhydride (PMDA),
2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA),
and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexn-
e-1,2-dicarboxylic anhydride (CP).
[0035] By way of example but not by way of limitation, the diamine
includes at least one selected from the group consisting of
siliconediamine, bis(3-aminopropyl)ether ethane,
3,3'-diamino-4,4'-dihydr- oxydiphenylsulfone (SO2-HOAB),
4,4'-diamino-3,3'-dihydroxybiphenyl (HOAB),
2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HOCF3AB),
siloxanediamine, bis(3-aminopropyl)ether ethane,
N,N-bis(3-aminopropyl)et- her, 1,4-bis(3-aminopropyl)piperazine,
isophoronediamine, 1,3'-bis(aminomethyl)cyclohexane,
3,3'-dimethyl-4,4'-diaminodicylohexylme- thane, 4,4'-methylenebis
(cyclohexylamine), 4,4'-diaminodiphenyl ether (p-DADE),
3,4'-diaminodiphenyl ether (m-DADE), 3,3-diaminodiphenyl ether,
4,4'-diamino-diphenylsulfone (p-DDS), 3,4'-diamino-diphenylsulfone,
3,3'-diamino-diphenylsulfone, 2,4'-diaminodiphenyl ether,
1,3-bis(4-aminophenoxy)benzene (m-TPE),
1,3-bis(3-aminophenoxy)benzene (APB),
2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP),
2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HF-BAPP),
bis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS),
bis[4-(3-aminophenoxy)phen- yl]sulfone (m-BAPS),
4,4'-bis(4-aminophenoxy)biphenyl (BAPB), 1,4-bis(4-aminophenoxy)
benzene (p-TPE), 4,4'-diaminodiphenylsulfide (ASD),
3,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfide,
3,3'-diamino-4,4'-dihydorxydipheylsulfone, 2,4-diaminotoluene
(DAT), 2,5-diaminotoluene, 3,5-diaminobenzoic acid (DABz),
2,6-diaminopyridine (DAPy), 4,4'-diamino-3,3'-dimethoxy-biphenyl
(CH3OAB), 4,4'-diamino-3,3'-dimethylbiphenyl (CH3AB), and
9,9'-bis(4-aminophenyl)fl- uorene (FDA).
[0036] Examples of the siliconediamine are BY16-853U and BY16-853C
made by Toray Dow Coning Silicone Co., Ltd., and X-22-16660B-3,
KF-8010 and X-22-161A made by the Shin-Etsu Chemical Co., Ltd.
[0037] The block copolymerization polyimide in the ketone, ether or
ester or a mixed solvent thereof may be prepared by heating the
tetracarboxylic dianhydride and diamine in the ketone, ether or
ester or a mixed solvent thereof and in the presence of an acid
catalyst generated from .gamma.-valerolcatone and a base, thereby
subjecting them to dehydration and imide-formation reactions,
wherein water formed during the reaction is discharged out of a
reaction system by azeotropy with the reaction solvent.
[0038] The block copolymerization type polyimide according to the
invention may be synthesized by using as the catalyst an acid that
is generated from .gamma.-valerolactone and a base selected from
pyridine, N-methylmorpholine or the like via such an equilibrium
reaction as set forth below. 1
[0039] A multicomponent block copolymer may be improved by
incorporation of a functional moiety and a structural moiety per
molecule in terms of photosensitivity, adhesion, water repellency,
mechanical properties, etc. Further, if a solvent-soluble polyimide
oligomer is formed through the first-stage reaction, it is then
possible to increase the solubility of a polyimide that is less
soluble in ketones, ethers or esters or a mixed solvent
thereof.
[0040] The ketone used herein should have a boiling point of
60.degree. C. to 200.degree. C. inclusive, because it is required
for the polyimide to be easily handled at coating and mixing steps
and for the solvent to be easily removable after molding.
[0041] Specifically but not exclusively, the ketone used herein
includes methyl ethyl ketone, methyl propyl ketone, methyl
isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone,
methyl n-hexyl ketone, diethyl ketone, diisopropyl ketone,
diisobutyl ketone, cyclopentanone, cylcohexanone,
methylcyclohexanone, acetylacetone, diacetone alcohol,
cyclohexen-1-one, .gamma.-butyrolactone, .gamma.-valerolactone,
.gamma.-caprolactone, .gamma.-heptalactone,
.alpha.-acetyl-.gamma.-butyro- lactone, and
.epsilon.-caprolactone.
[0042] Among others, cyclohexanone, methyi ethyl ketone, methyl
isobutyl ketone, acetylacetone, diacetone alcohol, cyclohexen-1-one
and .gamma.-butyrolactone are preferred because of being
general-purpose solvents.
[0043] The ether used herein should have a boiling point of
60.degree. C. to 200.degree. C. inclusive, because it is required
for the polyimide to be easily handled at coating and mixing steps
and for the solvent to be easily removable after molding.
[0044] By way of example but not by way of limitation, such an
ether includes dipropyl ether, diisopropyl ether, dibutyl ether,
tetrahydrofuran, tetrahydropyran, ethyl isoamyl ether,
ethyl-t-butyl ether, ethyl benzyl ether, cresyl methyl ether,
anisole, phenetole, diethylene glycol, diethylene glycol dimethyl
ether, triethylene glycol dimethyl ether, diethylene glycol diethyl
ether, and diethylene glycol dibutyl ether.
[0045] Among others, tetrahydrofuran, anisole, phenetole,
diethylene glycol dimethyl ether and triethylene glycol dimethyl
ether are preferred because of being general-purpose solvents.
[0046] Specifically but not exclusively, the ester herein used as
the solvent includes at least one selected from the group
consisting of methyl acetate, ethyl acetate, propyl acetate,
isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate,
isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate,
methylcyclohexyl acetate, benzyl acetate, methyl acetoacetate,
ethyl acetoacetate, methyl propionate, ethyl propionate, butyl
propionate, benzyl propionate, methyl butyrate, ethyl butyrate,
isopropyl butyrate, butyl butyrate, isoamyl butyrate, methyl
lactate, ethyl lactate, butyl lactate, ethyl isovalerate, isoamyl
isovalerate, diethyl oxalate, dibutyl oxalate, methyl benzoate,
ethyl benzoate, propyl benzoate and methyl salicylate.
[0047] The ketone, ether and ester may be used alone or in
admixture, and mixing allows the solubility of the polyimide to be
adjusted. The mixing ratio may be determined depending on the
desired properties and applications of the polyimide.
[0048] In particular, the mixed solvent is more preferred because
the polyimide resin composition can stably be used at the coating
and drying steps.
[0049] Although depending on composition, some polymers are less
soluble in the ketone, ether or ester or a ketone-ether mixed
solvent. In this case, the solvent may be mixed with
N,N-methylpyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, dimethylsulfoxide or like other polar
solvents in an amount of up to 40% by mass, and preferably 20% by
mass per the total amount of all solvents. Such a polar solvent
should not be used in an amount of greater than 40% by mass or else
whitening or other problems would arise, and should preferably be
used in combination with an azeotropic solvent such as toluene.
[0050] While the synthesis of polyimide has been described with
reference to the use of the ketone, ether or ester or a mixed
solvent thereof, it is understood that the polyimide may be
prepared only by use of a polar solvent such as
N,N-methylpyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, and dimethylsulfoxide. After synthesis, the
polyimide is precipitated in a poor solvent for its separation, and
then the separated polyimide is dissolved in the ketone or ether or
a mixed solvent thereof.
[0051] Specifically, a polyimide is synthesized in a polar solvent
well known as a solvent for polyimides, for instance,
N,N-methylpyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, or dimethylsulfoxide. In this case, that
solvent must be replaced by a ketone or an ether after synthesis;
however, this replacement is not easy because those solvents have
high boiling points.
[0052] Accordingly, the polyimide should be precipitated with a
poor solvent such as methanol for removal of the reaction solvent,
and procedures used for refinement of normal synthetic resins apply
to those steps.
[0053] Then, the resin is separated, followed by filtration and
drying. The dried block copolymerization polyimide powders are
dissolvable in the ketone, ether or ester or a mixed solvent
thereof, and the time taken for dissolution may be cut back by
heating the solvent to its boiling point or stirring the
solvent.
[0054] As the molecular weight of polyimide becomes high, the
solubility of polyimide in a given solvent becomes low; the
weight-average molecular weight of the inventive polyimide soluble
in ketones, ethers or esters or their mixed solvents should
preferably be in the range of 10,000 to 200,000 as calculated on a
polystyrene basis.
[0055] When the inventive block copolymerization type polyimide
composition is converted to a photosensitive polyimide, a
photooxygenation agent that generates an acid upon light
irradiation is introduced in that polyimide composition for
conversion to a positive type photosensitive polyimide
composition.
[0056] By way of example but not by way of limitation, the
photooxygenation agent to be added to the polyimide solution
includes a low-molecular-weight aromatic hydroxy compound such as
1,2-naphthoquinone-2-dizido-5-sulfonic acid ester and
1,2-naphthoquinone-2-diazido-4-sulfonic acid ester,
1,2-naphthoquinone-2-diazido-5-sulfonic acid-o-cresol ester, and
1,2-naphthoquinone-2-diazido-5-sulfonic acid-p-cresol ester.
[0057] Such a photooxygenation agent should preferably be used in
an amount of 6 to 35% by mass per polyimide solid content, although
that amount must be controlled depending on the thickness of the
coating film to be formed, etc.
[0058] The positive type photosensitive polyimide composition of
the invention may be formed in a given polyimide pattern on a
support substrate via various steps including coating, prebaking,
exposure, development and solvent removal steps. At the coating and
prebaking step, the photosensitive polyimide is coated on a
substrate such as a semiconductor disk, silicone wafer, germanium,
gallium arsenide, glass, ceramic, copper foil or printed substrate
by means of a spinner, roll coater, die coater or screen printing,
and then prebaked by means of a hot plate or oven.
[0059] Then, at the exposure step, a positive type photosensitive
composition found in a film form on the support substrate is
irradiated with active light rays such as ultraviolet radiation for
exposure, thereby forming indene carboxylate at an exposed site,
which will make a solubility difference between the exposed site
and an unexposed site at the subsequent development step.
[0060] At the development step, the exposed portion is removed by
means of a developing solution, thereby obtaining a relief pattern.
The developer used herein, for instance, includes sodium hydroxide,
potassium hydroxide, and tetramethylammonium hydroxide.
[0061] Often, the surface of the polyimide after the prebaking
step, because of its hydrophobicity, is less compatible with the
developer at the development step. In this case, it is acceptable
to add to the developer a solvent such as N-methylpyrrolidone, or
an alcohol or a surfactant.
[0062] The polymer has already been converted to a polyimide at the
synthesis stage. At the final heat treatment step, therefore,
polyamic acid must usually be dehydrated and converted to an imide
at about 350.degree. C. after pattern formation. In the process of
the invention, however, heat treatment at as low as 250.degree. C.
could be carried out because only evaporation of the solvent
contained in the pattern is needed. Preferably, the heat treatment
should be carried out at incremental temperatures of, for instance,
90.degree. C., 120.degree. C., 180.degree. C. and 250.degree.
C.
[0063] The solvent-insoluble filler to be mixed with an ink
comprising the inventive polyimide, for instance, includes an
inorganic filler selected from fumed silica, spherical silica,
amorphous silica, milled fiber, titanium dioxide, barium sulfate,
calcium carbonate, magnesium oxide and carbon black, a synthetic
resin filler selected from fluororesin, polyethylene resin,
polypropylene resin, crosslinked styrene, epoxy resin and polyimide
resin, and an organic pigment selected from phthalocyanine blue,
phthalocyanine green, isoindolinone yellow greenish, isoindolinone
yellow redish and quinacridone.
[0064] The amount of the filler added is preferably in the range of
0.05 to 95% by mass per polyimide solid content. More preferably,
fumed silica is used in an amount of 0.05 to 15% by mass per
polyimide solid content. Spherical silica, amorphous silica, milled
fiber, titanium dioxide, barium sulfate, calcium carbonate,
magnesium oxide, and carbon black is used in an amount of 1 to 50%
by mass per polyimide solid content.
[0065] The synthetic resin filler is used in an amount of
preferably 1 to 50% by mass per polyimide solid content, and the
organic pigment is used in an amount of 0.05 to 10% by weight per
polyimide solid content.
[0066] At a printing process, the positive type photosensitive
polyimide ink is printed all over the surface of an application
member using a metal mask, screen stencil or metal mesh. Then, an
image is exposed to ultraviolet radiation of 365 to 436 nm through
a given photomask, and the thus irradiated area is removed by an
alkaline aqueous solution so that a pattern can be formed.
[0067] When a film is formed by screen printing, it is preferable
to use a clearance of about 1/300 of the internal size of a screen
frame, a squeegee pressure of 100 to 300 g/cm.sup.2, a squeegee
angle of 65 to 750 and a squeegee rate of 40 to 150 mm/sec.
EXAMPLE 1-1
[0068] Four point four one (4.41) grams (15 mmoles) of
3,4,3',4'-biphenyltetracarboxylic dianhydride (made by Ube Kosan
Co., Ltd. with a molecular weight of 294.25; hereinafter BPDA for
short), 12.32 grams (30 mmoles) of
2,2-bis(4-(4-aminophenoxy)phenyl]propane (made by Wakayama Seika
Co., Ltd. with a molecular weight of 410.5; hereinafter BAPP for
short), 0.15 gram (1.5 mmoles) of .gamma.-valerolactone and 2.4
grams of (3 mmoles) of pyridine, both acting together as a
catalyst, and 64.75 grams of a solvent anisole were provided as a
starting feed.
[0069] First, the starting feed was stirred at 25.degree. C. and
100 rpm for 0.5 hour in a nitrogen atmosphere into a homogeneous
solution, which was in turn heated to 180.degree. C. in an oil
bath, where the solution was stirred at 180 rpm for a further one
hour. During the resulting reaction, azeotropic water was
removed.
[0070] After the completion of the first-stage reaction, the
reaction product was cooled down to 25.degree. C., and 8.83 grams
(30 mmoles) of fresh BPDA, 13.80 grams (15 mmoles) of
siliconediamine (By16-853U made by Toray Dow Coning Co., Ltd.) and
150 grams of a fresh solvent anisole were provided thereto. The
solution was stirred at 25.degree. C. and 100 rpm for about 1 hour,
and then heated to 180.degree. C. in an oil bath for 2 hours 45
minutes for reaction, during which the ensuing water was removed
for each 1 hour.
[0071] The obtained polyimide solution was found to have a polymer
concentration of 15% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 9,225, a weight-average
molecular weight (Mw) of 21,437 and a Z-average molecular weight
(Mz) of 37,515 as calculated on a polystyrene basis, with
Mw/Mn=2.32 and Mz/Mn=4.07.
EXAMPLE 1-2
[0072] Five point eight eight (5.88) grams (20 mmoles) of BPDA,
9.20 grams (10 mmoles) of siliconediamine (By16-853U made by Toray
Dow Coning Co., Ltd. with an amine equivalent of 460), and 0.3 gram
(3 mmoles) of .gamma.-valerolactone and 0.47 gram of (6 mmoles) of
pyridine, both acting together as a catalyst, 40 grams of a solvent
anisole and 11 grams of N-methylpyrrolidone (NMP) were provided as
a starting feed. First, the starting feed was stirred at 25.degree.
C. and 100 rpm for 0.5 hour in a nitrogen atmosphere into a
homogeneous solution, which was in turn heated to 180.degree. C. in
an oil bath, where the solution was stirred at 180 rpm for a
further one hour. During the resulting reaction, azeotropic water
was removed.
[0073] After the completion of the first-stage reaction, the
reaction product was cooled down to 25.degree. C., and 2.48 grams
(10 mmoles) of bicyclo[2,2,2]octa-2-ene-2,3,5,6-tetracarboxylic
dianhydride (made by Aldrich Co., Ltd. with a molecular weight of
248.19; hereinafter BCD for short), 3.41 grams (20 mmoles) of
isophoronediamine (made by Tokyo Kasei Co., Ltd. with a molecular
weight of 170.25) and 39.56 grams of a fresh solvent anisole were
provided thereto. The solution was stirred at 25.degree. C. and 100
rpm for about 1 hour, and then heated to 180.degree. C. in an oil
bath for 4 hours for reaction, during which the ensuing water was
removed per 1 hour.
[0074] The obtained polyimide solution was found to have a polymer
concentration of 18% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 11,481, a weight-average
molecular weight (Mw) of 24,431 and a Z-average molecular weight
(Mz) of 39,756 as calculated on a polystyrene basis, with
Mw/Mn=2.13 and Mz/Mn=3.38.
EXAMPLE 1-3
[0075] Ten point five seven (10.57) grams (40 mmoles) of
5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic
anhydride (made by Tokyo Kasei Co., Ltd. with a molecular weight of
264.23; hereinafter CP acid for short), 8.65 grams (20 mmoles) of
bis[4-(3-amino-phenoxy)phenyl]sulfone (made by Wakayama Seika Co.,
Ltd. with a molecular weight of 432.5; hereinafter m-BAPS for
short), and 0.4 gram (4 mmoles) of .gamma.-valerolactone and 0.63
gram of (8 mmoles) of pyridine, both acting together as a catalyst,
and 20 grams of a solvent cyclohexanone were provided as a starting
feed. First, the starting feed was stirred at 25.degree. C. and 100
rpm for 0.5 hour in a nitrogen atmosphere into a homogeneous
solution, which was in turn heated in an oil bath at 180.degree.
C., where the solution was stirred at 180 rpm for a further one
hour. During the resulting reaction, azeotropic water was
removed.
[0076] After the completion of the first-stage reaction, the
reaction product was cooled down to room temperature, and 8.21
grams (20 mmoles) of a fresh BAPP and 40.64 grams of a fresh
solvent cyclohexanone were provided thereto. The solution was
stirred at 25.degree. C. and 100 rpm for about 1 hour, and then
heated to 180.degree. C. in an oil bath, where it was stirred at
180 rpm for 2 hours for reaction, during which the ensuing water
was removed per 1 hour.
[0077] The obtained polyimide solution was found to have a polymer
concentration of 30% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 7,042, a weight-average
molecular weight (Mw) of 11,574 and a Z-average molecular weight
(Mz) of 17,551 as calculated on a polystyrene basis, with
Mw/Mn=1.64 and Mz/Mn=2.49.
EXAMPLE 1-4
[0078] Thirty five point three one (35.31) grams (120 mmoles) of
BPDA, 55.54 grams (60 mmoles) of siliconediamine (By16-853U made by
Toray Dow Coning Co., Ltd. with an amine equivalent of 460), and
1.8 grams (18 mmoles) of .gamma.-valerolactone and 2.85 gram of (36
mmoles) of pyridine, both acting together as a catalyst, and 150
grams of N-methylpyrrolidone (NMP) and 40 grams of toluene were
provided as a starting feed, which was then stirred at 25.degree.
C. and 100 rpm for 0.5 hour in a nitrogen atmosphere into a
homogeneous solution, which was in turn heated to 180.degree. C. in
an oil bath, where the solution was stirred at 180 rpm for a
further one hour. During the resulting reaction, an azeotropic
component of toluene and water was removed.
[0079] After the completion of the first-stage reaction, the
reaction product was cooled down to room temperature, and 17.65
grams (60 mmoles) of a fresh BPDA, 27.60 grams (30 mmoles) of
siliconediamine (By16-853U made by Toray Dow Coning Co., Ltd.),
12.01 grams (60 mmoles) of 3,4'-diaminodiphenyl ether (made by
Wakayama Seika Co., Ltd. with a molecular weight of 200.2;
hereinafter m-DADE for short), 8.77 grams (30 mmoles) of
1,3-bis(4-aminophenoxy) benzene (made by Wakayama Seika Co., Ltd.
with a molecular weight of 292.34; hereinafter m-TPE for short),
200 grams of a fresh solvent N-methylpyrrolidone (NMP) and 30 grams
of a fresh toluene were provided thereto. The solution was stirred
at 25.degree. C. and 100 rpm for 1 hour, and then heated to
180.degree. C. in an oil bath for 4 hours 30 minutes for reaction,
during which the ensuing azeotropic product of toluene and water
was removed per 1 hour.
[0080] The obtained polyimide solution was found to have a polymer
concentration of 30% by mass.
[0081] The obtained polyimide solution was cooled down to
25.degree. C. Then, while stirring was carried out, the solution
was mixed with small portions of methanol, and the resultant
polyimide precipitate was comminuted. The resultant polyimide
powders were washed three times with methanol, and subjected to
suction filtration. Using a vacuum drier, the thus obtained
polyimide powders were dried at 25.degree. C. for 3 hours,
60.degree. C. for a further one hour, and 90.degree. C. for a
further one hour.
[0082] The dried polyimide powders were agitated at 25.degree. C.
for 30 minutes with the addition of anisole thereto until a solid
content of 24% by mass was obtained. A most part of the powders was
found to stay in a powdery form although only a small portion
thereof was dissolved. A 30-minute agitation at an elevated
temperature of 100.degree. C. enabled the polyimide powders to be
dissolved in anisole, yielding a homogeneous solution, which was
found to keep fluidity even upon cooled down to 25.degree. C. As
measured by gel permeation chromatography (GPC), the polyimide was
found to have a number-average molecular weight (Mn) of 13,890, a
weight-average molecular weight (Mw) of 31,456 and a Z-average
molecular weight (Mz) of 47,203 as calculated on a polystyrene
basis, with Mw/Mn=2.26 and Mz/Mn=3.39.
[0083] Even after a lapse of 2 weeks, there was no increase in the
viscosity of the polyimide solution; that solution kept still
fluidity. In an environment having a temperature of 25.degree. C.
and a relative humidity of 60%, this solution was used to make a
screen printing ink. While a three-roll arrangement is used to mix
a filler with a polyimide vanish by roll milling, the polyimide is
highly sensitive to atmospheric moisture because the surface area
of the polyimide coming into contact with the air increases. When
anisole that is a sort of ether is used as in the present
invention, however, the polyimide is hardly affected by atmospheric
moisture during roll milling. Even 40 minutes after exposure of the
inventive polyimide to air, there was no whitening of its
surface.
EXAMPLE 1-5
[0084] Twenty five point seven eight (25.78) grams (80 mmoles) of
3,4,3',4'-benzophenonetetracarboxylic dianhydride (a product made
by Jayhawk Fine Chemicals Co., Ltd. with a molecular weight of
322.23; hereinafter BTDA for short), 6.81 grams (40 mmoles) of
isophoronediamine, and 1.20 grams (12 mmoles) of
.gamma.-valerolactone and 1.90 grams (24 mmoles) of pyridine, both
acting together as a catalyst, and 100 grams of a solvent
N-methylpyrrolidone and 30 grams of a solvent toluene were provided
as a starting feed, which was then stirred at 25.degree. C. and 100
rpm for 30 minutes in a nitrogen atmosphere into a homogeneous
solution. The solution was heated to 180.degree. C., followed by
stirring at 180 rpm for 1 hour. During the reaction, the resultant
water and the ensuing azeotropic component of water and toluene
were removed.
[0085] The solution was cooled down to 25.degree. C., and 34.6
grams (80 mmoles) of m-BAPS, 9.05 grams (40 mmoles) of
cyclohexane-1,2,4,5-tetracar- boxylic dianhydride (made by
Shin-Nippon Rika Co., Ltd. with a molecular weight of 226.25;
hereinafter H-PMDA for short), 115.76 grams of a solvent
N-methylpyrrolidone and 30 grams of toluene were added thereto,
followed by a one-hour stirring at 25.degree. C. and, then, a
three-hour stirring at 180.degree. C. and 180 rpm in an oil bath.
The thus obtained polyimide solution was found to have a polymer
concentration of 25% by mass.
[0086] The obtained polyimide solution was cooled down to
25.degree. C., and small portions of methanol were added thereto
under agitation. The obtained polyimide precipitate was comminuted
in a mixer, and the resulting polyimide powders were filtrated and
washed three times with methanol. The thus obtained polyimide
powders were dried at room temperature for 3 hours, 60.degree. C.
for a further one hour, and 90.degree. C. for a further one
hour.
[0087] The dried polyimide powders were agitated at 25.degree. C.
for 30 minutes with the addition of cyclohexanone thereto until a
solid content of 20% by mass was obtained. A most part of the
powders was found to stay in a powdery form although only a small
portion thereof was dissolved. A 30-minute agitation at an elevated
temperature of 100.degree. C. enabled the polyimide powders to be
dissolved in the solvent, yielding a homogeneous solution.
[0088] As measured by gel permeation chromatography (GPC), the
obtained polyimide was found to have a number-average molecular
weight (Mn) of 18,664, a weight-average molecular weight (Mw) of
102,276 and a Z-average molecular weight (Mz) of 325,769 as
calculated on a polystyrene basis, with Mw/Mn=5.47.
[0089] Then, the polyimide solution was coated on a stainless steel
plate by means of a spinner, and allowed to stand alone in the air.
Even after a lapse of 30 minutes, there was no whitening of the
surface of the polyimide film.
COMPARATIVE EXAMPLE 1-1
[0090] In Example 1-4, the three-roll arrangement was used to
subject the solution of the polyimide in N-methylpyrrolidone to
roll milling with no separation of the powdery polyimide from the
N-methylpyrrolidone solution. During roll milling, the polyimide
was affected by atmospheric moisture due to an increase in its
surface area coming into contact with the air, and after a lapse of
10 minutes, the surface of the polyimide was whitened.
COMPARATIVE EXAMPLE 1-2
[0091] In Example 1-5, the three-roll arrangement was used to
subject the solution of the polyimide in N-methylpyrrolidone to
roll milling with no separation of the powdery polyimide from the
N-methylpyrrolidone solution. During roll milling, the polyimide
was affected by atmospheric moisture due to an increase in its
surface area coming into contact with the air; after a lapse of 5
minutes, the surface of the polyimide became white little by little
from its periphery, resulting in whitening of the whole surface
after a lapse of 10 minutes.
EXAMPLE 2-1
[0092] Charged in a four-necked flask having a stirrer, a
ball-equipped condenser and a nitrogen inlet pipe were 14.88 grams
(60 mmoles) of BCD, 6.00 grams (30 mmoles) of 4,4'-diaminodiphenyl
ether (made by Wakayama Seika Co., Ltd. with a molecular weight of
200.00; hereinafter p-DADE for short), and 0.9 gram (9 mmmoles) of
.gamma.-valerolactone and 1.44 grams (18 mmoles) of pyridine, both
acting together as a catalyst, and a solvent .gamma.-butyrolactone.
Thirty (30) grams of toluene were added as a dehydrator to a
reaction system. First, the reaction system was stirred at room
temperature and 100 rpm for 10 minutes in a nitrogen atmosphere to
dissolve the monomers into a homogeneous solution, which was in
turn heated in an oil bath of 180.degree. C., and stirred at 180
rpm for 1 hour, during which azeotropic water was removed. After a
180 rpm, 180.degree. C. reaction, the first-stage reaction was
stopped. A sample was taken out of the reaction product for the
purpose of molecular weight measurement, and subjected to gel
permeation chromatography. As a result, the sample was found to
have a weight-average molecular weight of 4,300 with a molecular
weight distribution (Mw/Mn) of 1.8.
[0093] After the flask was cooled down to an internal temperature
of 60.degree. C., 6.00 grams (30 mmoles) of m-DADE and 10.87 grams
(30 mmoles) of 2,2-bis[4-(4-aminophenoxy) phenyl]hexafluoropropane
(made by Central Glass Co., Ltd. with a molecular weight of 362.33;
hereinafter HOCF3AB for short) were added to the reaction product
for homogeneous dissolution of the diamine. Then, 8.82 grams (30
mmoles) of BPDA were added together with a solvent
.gamma.-butyrolactone to the solution, and finally 30 grams of a
dehydrator toluene were placed in the flask.
[0094] Then, the solution was stirred at 25.degree. C. and 100 rpm
for 1 hour, and heated to 180.degree. C. in an oil bath, where it
was stirred at 180 rpm for 2 hours 45 minutes for reaction, during
which the resultant water was removed for each hour.
[0095] The obtained polyimide solution was found to have a polymer
concentration of 20% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 9,225, a weight-average
molecular weight (Mw) of 21,437 and a Z-average molecular weight
(Mz) of 37,515, with Mw/Mn=2.32 and Mz/Mn=4.07, as calculated on a
polystyrene basis.
[0096] A photooxygenation agent
1,2-naphthoquinone-2-diazido-5-sufonic acid ester (made by Toyo
Synthesis Industries, Ltd.; hereinafter PC5 for short) was added to
the obtained block copolymerization type polyimide solution in an
amount of 20% by mass relative to polyimide solid content, which
was then filtrated through a 0.3 .mu.m filter under pressure to
obtain a positive type photosensitive polyimide composition.
[0097] In an environment having a relative humidity of 80%, the
obtained positive type photosensitive polyimide composition was
coated on a silicon wafer by means of a rotary spinner, so that a
uniform film with no sign of whitening could be formed.
Subsequently, the film was prebaked on a hot plate at 90.degree. C.
for 10 minutes to obtain a 6.5 .mu.m film, which was in turn
exposed to light at a varying exposure of 400 to 800 mJ/cm.sup.2 by
way of a resolution-measuring mask.
[0098] Then, using a 5% by mass solution of tetramethyl-ammonium
hydroxide as a developing solution, paddle development was carried
out at room temperature for 7 minutes, followed by rinsing with
pure water, yielding a relief pattern.
[0099] The obtained pattern was observed under a scanning electron
microscope. A sensitivity to 10 .mu.mL/S was 700 mJ/cm.sup.2. The
obtained relief pattern was dried and heat treated at three stages,
say, 120.degree. C., 180.degree. C. and 250.degree. C., each for 20
minutes, by means of a hot-air drier, so that a satisfactory
polyimide film pattern could be obtained. The rate of film
remaining at an unexposed site was 78%.
EXAMPLES 2-2 TO 2-8
[0100] A block copolymerization type polyimide composition was
prepared as in Example 2-1 with the exception that the
tetracarboxylic dianhydride and diamine for the first-stage
reaction and the tetracarboxylic dianhydride and diamine for the
second-stage reaction were changed to those shown in Table 1,
respectively. Then, a positive type photosensitive polyimide
composition was prepared and estimated as in Example 2-1. The
results are shown in Table 1.
1 TABLE 1 First-Stage Reaction Example No. TCDA* Amount (mmole)
Diamine Amount (mmole) Ex. 2-2 BPDA 30 BY16-853U 60 Ex. 2-3 ODPA 60
SO2-HOAB 30 Ex. 2-4 BCD 60 p-DADE 30 Ex. 2-5 BCD 30 HOAB 60 Ex. 2-6
BTDA 60 KF-8010 30 Ex. 2-7 BCD 60 m-DADE 30 Ex. 2-8 BPDA 30
SO2-HOAB 60 Second-Stage Reaction Amount Amount Example No. TCDA*
(mmole) Diamine (mmole) Mw** Thickness Resolution Ex. 2-2 BCD 60
HOCF3AB 30 45,000 4 .mu.m 2 .mu.m Ex. 2-3 BPDA 30 p-DDS 60 40,000
10 .mu.m 20 .mu.m Ex. 2-4 ODPA 30 HOAB 60 50,200 20 .mu.m 25 .mu.m
Ex. 2-5 BPDA 60 p-DDS 30 55,200 18 .mu.m 20 .mu.m Ex. 2-6 BPDA 30
SO2-HOAB 30 38,000 15 .mu.m 20 .mu.m p-DDS 30 Ex. 2-7 BPDA 30
SO2-HOAB 60 48,000 20 .mu.m 25 .mu.m Ex. 2-8 BTDA 60 p-DDS 30
33,000 15 .mu.m 30 .mu.m TADA*: Tetracarboxylic dianhydride Mw**:
Molecular weight
EXAMPLE 3-1
[0101] Charged in a four-necked flask having a stirring rod, a
ball-equipped condenser and a nitrogen inlet pipe were 14.88 grams
(60 mmoles) of BCD, 6.00 grams (30 mmoles) of p-DADE, and 0.9 gram
(9 mmoles) of .gamma.-valerolactone and 1.44 grams (18 mmoles) of
pyridine, both acting together as a catalyst, and a solvent
.gamma.-butyrolactone.
[0102] For azeotropic removal of water, 30 grams of toluene were
added as a dehydrator to a reaction system.
[0103] First, the reaction system was stirred at 25.degree. C. ad
100 rpm for 10 minutes in a nitrogen atmosphere to dissolve the
monomers into a homogeneous solution, which was in turn heated to
180.degree. C. in an oil bath, and stirred at 180 rpm for 1 hour,
during which azeotropic water was removed.
[0104] After a 180 rpm, 180.degree. C. reaction, the first-stage
reaction was stopped. A sample was taken out of the reaction
product for the purpose of molecular weight measurement, and
subjected to gel permeation chromatography. As a result, the sample
was found to have a weight-average molecular weight of 4,300 with a
molecular weight distribution (Mw/Mn) of 1.8.
[0105] After the flask was cooled down to an internal temperature
of 60.degree. C., the second-stage reaction was initiated; 6.00
grams (30 mmoles) of m-DADE and 10.87 grams (30 mmoles) of
HO--CF.sub.3-AB were added to the reaction product for homogeneous
dissolution of the diamine. Then, 8.82 grams (30 mmoles) of
biphenyltetracarboxylic dianhydride (made by Ube Kosan Co., Ltd.
with a molecular weight of 294.33; hereinafter BPDA for short) were
added together with a solvent .gamma.-butyrolactone to the
solution, and finally 30 grams of toluene were placed in the
flask.
[0106] Then, the solution was stirred at 25.degree. C. and 100 rpm
for 1 hour, and heated in an oil bath of 180.degree. C., where it
was stirred at 180 rpm for 2 hours 45 minutes for reaction, during
which the resultant water was removed for each hour.
[0107] The obtained polyimide solution was found to have a polymer
concentration of 20% by mass. As measured by gel permeation
chromatography, the polyimide was found to have a number-average
molecular weight (Mn) of 9,225, a weight-average molecular weight
(Mw) of 21,437 and a Z-average molecular weight (Mz) of 37,515,
with Mw/Mn=2.32 and Mz/Mn=4.07, as calculated on a polystyrene
basis.
[0108] Fumed silica (R-200 made by Nippon Aerosil Co., Ltd.) was
added to the obtained block copolymerization polyimide solution in
an amount of 1.0% by mass relative to polyimide resin for
full-mixing with a three-roll arrangement. Subsequently, a
photooxygenation agent 1,2-naphthoquinone-2-diazido-5-sufonic acid
ester (made by Toyo Synthesis Industries, Ltd.; hereinafter PC5 for
short) was added to the block copolymerization polyimide solution
in an amount of 20% by mass relative to polyimide solid content to
obtain a positive type photosensitive polyimide ink.
[0109] The obtained positive type photosensitive polyimide
composition ink was used on a 400-mesh screen printing plate to
form a photosensitive film on a wafer at a squeegee rate of 10
mm/sec., and the film was prebaked on a hot plate at 90.degree. C.
for 10 minutes to obtain a 6.5 .mu.m film, which was then exposed
to ultraviolet radiation at an exposure of 800 mJ/cm.sup.2 by way
of a mask.
[0110] Then, using a 5% by mass aqueous solution of
tetramethyl-ammonium hydroxide as a developing solution,
development was carried out at room temperature for 7 minutes,
followed by rinsing with pure water, yielding a relief pattern. The
obtained relief pattern was dried at three stages, say, 120.degree.
C., 180.degree. C. and 250.degree. C., each for 20 minutes, by
means of a hot-air drier. Observation of the relief pattern under a
scanning electron microscope showed that a 1 .mu.m line-and-space
pattern was obtained. The rate of film remaining at an unexposed
site was then 78%.
EXAMPLES 3-2 TO 3-10
[0111] As in Example 3-1, polyimide oligomers comprising the
tetracarboxylic dianhydrides and diamines shown in Table 2 were
prepared. Subsequently, the tetracarboxylic dianhydrides and
diamines shown in Table 3 were added to the polyimide oligomers to
prepare block copolymerization type polyimide solutions. The
molecular weights of the obtained polyimides are shown in Table
2.
2TABLE 2 Polyimide Resin No. TCDA* Amount Diamine Amount Mw**
First-Stage Reaction 2 BPDA 60 mmoles SO2-HOAB 30 mmoles 2,800 3
BCD 60 p-DADE 30 3,200 4 ODPA 30 p-DDS 60 2,600 5 BCD 30 m-DADE 60
3,300 6 BPDA 60 BY16-853U 30 2,800 7 BCD 60 HOAB 30 3,500 8 BTDA 30
KF-8010 60 3,300 Second-Stage Reaction 2 BPDA 30 mmoles p-DDS 60
mmoles 45,000 3 BPDA 30 HOCF3AB 60 56,000 4 BPDA 60 SO2HOAB 30
38,000 5 BODA 60 HOCF3AB 30 42,000 6 ODPA 30 HOAB 60 65,000 7 BPDA
30 p-DDS 60 48,000 8 BPDA 60 SO2HOAB 30 58,000 TCDA*:
Tetracarboxylic dianhydride Mw*: Weight-average molecular
weight
[0112] The fillers shown in Table 3 were each added to the obtained
block copolymerization polyimide solution in an amount of 1.0% by
mass for mixing with a three-roll arrangement. Subsequently, a
photooxygenation agent 1,2-naphthoquinone-2-diazido-5-sufonic acid
ester (made by Toyo Synthesis Industries, Ltd.) was added to the
block copolymerization polyimide solution in an amount of 20% by
mass relative to polyimide solid content to obtain a positive type
photosensitive polyimide composition ink as shown in Table 3.
[0113] In a room having a relative humidity of 80%, the obtained
positive type photosensitive polyimide composition ink was used on
a 400-mesh screen printing plate to form a photosensitive film on a
copper foil at a squeegee rate of 10 mm/sec., and the film was
prebaked on a hot plate at 90.degree. C. for 10 minutes to obtain a
6.5 .mu.m thick film, which was then exposed to ultraviolet
radiation at an exposure of 800 mJ/cm.sup.2 by way of a
resolution-measuring mask. Then, using a 5% by mass aqueous
solution of sodium hydroxide as a developing solution, development
was carried out at 25.degree. C. for 5 minutes, followed by rinsing
with pure water. The obtained relief pattern was then dried at
three stages, say, 120.degree. C., 180.degree. C. and 250.degree.
C., each for 20 minutes, by means of a hot-air drier.
[0114] Observation of the relief pattern under a scanning electron
microscope showed that a satisfactory line-and-space pattern was
obtained. The resolutions at which good line-and-space patterns
could be obtained are shown in Table 3.
[0115] In Table 3, it is noted that silica products obtained by wet
processes are designated in terms of number base particle
diameter.
3 TABLE 3 Particle Diameter Amount Polyimide Type of of Filler, of
Filler, Resin No. Filler 1 .mu.m wt % Ex. 3-2 2 Fumed Silica 0.016
5 Ex. 3-3 2 Fumed Silica 0.016 10 Ex. 3-4 3 Fumed Silica 0.016 5
Ex. 3-5 3 Fumed Silica 0.016 7 Ex. 3-6 4 Fumed Silica 0.016 5 Ex.
3-7 5 Fumed Silica 0.016 10 Ex. 3-8 6 Silica 3 10 Ex. 3-9 6 Silica
3 10 Ex. 3-10 7 Fumed Silica 0.016 5 Particle Diameter Amount
Polyimide Type of of Filler, of Filler, Resin No. Filler 2 .mu.m wt
% Ex. 3-2 2 Spherical Silica 0.5 30 Ex. 3-3 2 Spherical Silica 0.5
5 Ex. 3-4 3 Titanium Oxide 3 15 Ex. 3-5 3 Barium Sulfate 3 15 Ex.
3-6 4 Polyimide Resin 5 30 Ex. 3-7 5 Phthalo- 0.1 3 cyanine Green
Ex. 3-8 6 Phthalo- 0.1 3 cyanine Blue Ex. 3-9 6 -- -- -- Ex. 3-10 7
Silica 3 50 Particle Diameter Amount Polyimide Type of of Filler,
of Filler, Resin No. Filler 3 .mu.m wt % Ex. 3-2 2 -- -- -- Ex. 3-3
2 -- -- -- Ex. 3-4 3 -- -- -- Ex. 3-5 3 -- -- -- Ex. 3-6 4 -- -- --
Ex. 3-7 5 -- -- -- Ex. 3-8 6 -- -- -- Ex. 3-9 6 -- -- -- Ex. 3-10 7
Phthalo- 0.1 5 cyanine Blue
EXAMPLE 3-11
[0116] Thirty seven point two three (37.23) grams (120 mmoles) of
3,3',4,4'-biphenyl ether tetracarboxylic dianhydride (made by
Manack Co., Ltd.; hereinafter ODPA for short), 53.64 grams (60
mmoles) of diaminosiloxane (Lot No. By16-853U made by Toray Dow
Coning Silicone Co., Ltd. with an amine equivalent of 447), and 1.2
grams (12 mmoles) of .gamma.-valerolactone and 1.9 grams (24
mmoles) of pyridine, both acting together as a catalyst, 166 grams
of a solvent ethyl benzoate (hereinafter BAEt for short), 40 grams
of a solvent y-butyrolactone and 40 grams of a dehydration aid
toluene were provided as a starting feed.
[0117] First, the starting feed was stirred at 25.degree. C. and
100 rpm for 0.5 hour in a nitrogen atmosphere, and heated to
180.degree. C. in an oil bath, where it was stirred at 180 rpm for
a one-hour reaction, during which the resultant water was
removed.
[0118] The obtained imide oligomer was found to have a
number-average molecular weight (Mn) of 2,133 and a weight-average
molecular weight (Mw) of 3,200, with Mw/Mn=1.5.
[0119] After the completion of the first-stage reaction, the
reaction solution was cooled down to 25.degree. C. with the
introduction of 6.01 grams (30 mmoles) of m-DADE, 8.41 grams (30
mmoles) of 3,3'-diamino-4,4'-dihydroxydiphenyl-sulfone (made by
Konishi Chemicals Co., Ltd. with a molecular weight of 280.3;
hereinafter SO2-HOAB for short), 30 grams of a solvent
.gamma.-butyrolactone and 30 grams of toluene. After the reaction
system was stirred at room temperature and 100 rpm for about 1
hour, the bath was heated to 180.degree. C., at which the reaction
system was stirred at 180 rpm for 3 hours, during which the
resultant water was removed.
[0120] The obtained polyimide solution was found to have a polymer
concentration of 30% by mass. As measured by gel permeation
chromatography (CPS), the polyimide was found to have a
number-average molecular weight (Mn) of 28,571 and a weight-average
molecular weight (Mw) of 60,000, with Mw/Mn=2.1, as calculated on a
polystyrene basis.
[0121] Then, fumed silica (R-200 made by Nippon Aerosil Co., Ltd.)
that was an inorganic filler was added to the obtained polyimide
vanish in an amount of 10% by mass relative to polyimide solid
content for full mixing with a three-roll arrangement, followed by
addition of 1,2-naphthoquinone-2-diazido-5-sulfonic acid ester
(NT200 made by Toyo Synthesis Industries, Ltd.) in an amount of 15%
by mass relative to polyimide solid content, thereby preparing a
positive type photosensitive polyimide ink.
[0122] In a clean room at a temperature 24.degree. C. and a
relative humidity of 60%, the obtained positive type photosensitive
polyimide ink was used on a 300-mesh screen printing plate to form
a photosensitive film on a 35 .mu.m copper foil at a squeegee rate
of 20 mm/sec., following which the film was left for about 10
minutes for leveling. In the meantime, any whitening due to
absorption of moisture was not found on the surface of the
polyimide film.
[0123] Then, the film was prebaked at 90.degree. C. for 40 minutes
in a hot-air circulation drier to obtain an 8 .mu.m thick film,
which was then exposed to ultraviolet radiation at an exposure of
600 mJ/cm.sup.2 by way of a resolution-measuring mask.
[0124] Then, using a 3% by mass aqueous solution of sodium
hydroxide as a developing solution, development was carried out at
40.degree. C. for 2.5 minutes, followed by rinsing with pure water.
The obtained relief pattern was then dried at three stages, say,
120.degree. C., 180.degree. C. and 250.degree. C., each for 20
minutes, by means of a hot-air circulation drier. Observation of
the obtained relief pattern under a scanning electron microscope
showed that a satisfactory pattern was obtained.
COMPARATIVE EXAMPLE 2-1
[0125] Charged in a four-necked flask having a stirring rod, a
ball-equipped condenser and a nitrogen inlet pipe were 14.88 grams
(60 mmoles) of BCD, 6.00 grams (30 mmoles) of p-DADE, and 0.9 gram
(9 mmoles) of .gamma.-valerolactone and 1.44 grams (18 mmoles) of
pyridine, both acting together as a catalyst, and a solvent
N-methylpyrrolidone.
[0126] For azeotropic removal of water, 30 grams of toluene were
added as a dehydrator to a reaction system. First, the reaction
system was stirred at 25.degree. C. and 100 rpm for 10 minutes in a
nitrogen atmosphere to dissolve the monomers into a homogeneous
solution, which was in turn heated to 180.degree. C. in an oil
bath, and stirred at 180 rpm for 1 hour, during which azeotropic
water was removed.
[0127] A sample was taken out of the reaction product for the
purpose of molecular weight measurement, and subjected to gel
permeation chromatography. As a result, the sample was found to
have a weight-average molecular weight of 3,800 with a molecular
weight distribution (Mw/Mn) of 1.88.
[0128] Upon the flask cooled down to an internal temperature of
60.degree. C., the second-stage reaction was initiated; 6.00 grams
(30 mmoles) of m-DADE and 10.87 grams (30 mmoles) of
HO--CF.sub.3-AB were added to the reaction product for homogeneous
dissolution of the diamine. Then, 8.82 grams (30 mmoles) of BPDA
were added together with a solvent .gamma.-butyrolactone to the
solution, and finally 30 grams of a dehydrator toluene were added
thereto for azeotropic removal of water.
[0129] Then, the solution was stirred at 25.degree. C. and 100 rpm
for 1 hour, and heated to 180.degree. C. in an oil bath, at which
it was stirred at 180 rpm for 2 hours 45 minutes for reaction,
during which the resultant water was removed for each hour.
[0130] The obtained polyimide solution was found to have a polymer
concentration of 20% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 22,350 and a weight-average
molecular weight (Mw) of 49,000, with Mw/Mn=2.19, as calculated on
a polystyrene basis.
[0131] In an environment having a relative humidity of 80%, fumed
silica (R-200 made by Nippon Aerosil Co., Ltd.) was added to the
obtained block copolymerization polyimide solution in an amount of
1.0% by mass relative to polyimide resin for mixing with a
three-roll arrangement. However, no homogeneous ink was obtained
due to whitening.
COMPARATIVE EXAMPLE 2-2
[0132] Charged in a four-necked flask having a stirring rod, a
ball-equipped condenser and a nitrogen inlet pipe were 14.88 grams
(60 mmoles) of BCD, 6.00 grams (30 mmoles) of p-DADE, and 0.9 gram
(9 mmoles) of .gamma.-valerolactone and 1.44 grams (18 mmoles) of
pyridine, both acting together as a catalyst, and a solvent
N-methylpyrrolidone. For azeotropic removal of water, 30 grams of
toluene were added to a reaction system.
[0133] First, the reaction system was stirred at room temperature
and 100 rpm for 10 minutes in a nitrogen atmosphere to dissolve the
monomers into a homogeneous solution, which was in turn heated in
an oil bath of 180.degree. C., and stirred at 180 rpm for 1 hour,
during which azeotropic water was removed. After a 180.degree. C.,
180 rpm reaction, the first-stage reaction was stopped. A sample
was taken out of the reaction product for the purpose of molecular
weight measurement, and subjected to gel permeation chromatography.
As a result, the sample was found to have a weight-average
molecular weight of 3,800 with a molecular weight distribution
(Mw/Mn) of 1.88.
[0134] Upon the flask cooled down to an internal temperature of
60.degree. C., the second-stage reaction was initiated; 6.00 grams
(30 mmoles) of m-DADE and 10.87 grams (30 mmoles) of
HO--CF.sub.3-AB were added to the reaction product for homogeneous
dissolution of the diamine. Then, 8.82 grams (30 mmoles) of
3,3',4,4'-biphenyltetra-carboxylic dianhydride (made by Ube Kosan
Co., Ltd. with a molecular weight of 294.33; hereinafter BPDA for
short) were added together with a solvent .gamma.-butyrolactone to
the solution, and finally 30 grams of toluene were added thereto
for azeotropic removal of water.
[0135] Then, the solution was stirred at 25.degree. C. and 100 rpm
for 1 hour, and heated to 180.degree. C. in an oil bath, at which
it was stirred at 180 rpm for 2 hours 45 minutes for reaction,
during which the resultant water was removed for each hour.
[0136] The obtained polyimide solution was found to have a polymer
concentration of 19.5% by mass. As measured by gel permeation
chromatography (GPC), the polyimide was found to have a
number-average molecular weight (Mn) of 25,300 and a weight-average
molecular weight (Mw) of 53,200, with Mw/Mn=2.10, as calculated on
a polystyrene basis.
[0137] At a relative humidity of 20%, fumed silica (R-200 made by
Nippon Aerosil Co., Ltd.) was added to the block copolymerization
polyimide solution in an amount of 1.0% by mass relative to
polyimide resin for full-mixing with a three-roll arrangement. In
this case, uniform mixing was achievable. Subsequently,
1,2-naphthoquinone-2-diazido-5-sulfonic acid ester (NT200 made by
Toyo Synthesis Industries, Ltd.) was added to the solution in an
amount of 20% by mass relative to polyimide solid content, thereby
preparing a positive type photosensitive polyimide ink.
[0138] In an environment at a relative humidity of 75%, the
obtained positive type photosensitive polyimide composition ink was
used on a 400-mesh screen printing plate to form a photosensitive
film on a 30 .mu.m thick stainless foil at a squeegee rate of 10
mm/sec. After printing, however, the film became gradually white.
This whitening film was prebaked on a hot plate at 90.degree. C.
for 10 minutes, but was not restored to a transparent film.
[0139] The polyimide ink remained jammed in the screen mesh with an
increase in the viscosity of the polyimide ink on the screen plate;
printing could not be continued any longer.
INDUSTRIAL APPLICABILITY
[0140] The present invention can provide a block copolymerization
type polyimide that is never whitened in the air unlike prior art
solvent-soluble polyimides, and a positive type block
copolymerization polyimide prepared using the inventive polyimide
in combination with a photooxygenation agent, and an ink prepared
from it enables relief or other images to be formed with improved
resolution.
* * * * *